In the nursery industry, where large quantities of seedlings are grown, a great deal of time is spent in grading seedlings by size. The size of the seedling is an important factor in its value and is often a prerequisite for planting the seedlings by automated equipment. At the present time, seedlings are graded manually by visual measurement of the height of the seedling against a scale or rule and then depositing the seedling in a group according to size designation. This method is slow and involves considerable time and expense in manual labor.
A number of devices have been developed for automatically sorting and collecting various types of objects according to size so as to avoid the problems of manual sorting. Some of these employ photocell devices. However, most of these apparatus are designed to handle one specific type of product and are not adaptable or usable in the nursery industry to sort and collect seedling trees.
It is a primary object of the invention to develop a seedling grading machine for automatically sorting and collecting seedling trees according to size.